The present invention relates to an airbag module which has a gas generator, an ignition device and an airbag, and which is provided with a locking device and an electric contacting device which cause the airbag module to be mechanically locked when inserted into a receiving shaft provided in the vehicle and cause an electric connection to be established between the ignition device and a controller.
U.S. Pat. No. 6,007,087 describes such an airbag module, which may be inserted into a receiving shaft on the steering wheel. The locking device and the electric contacting are designed so that when the airbag module is inserted into the receiving shaft without the use of a tool, it is automatically locked mechanically and an electric connection is established between the airbag module and a controller. However, a special tool is needed to remove the airbag module from the receiving shaft. This facilitates insertion of the airbag module into the receiving shaft, but makes removal of the airbag module difficult.
There are situations in which an airbag should be deactivated urgently, so that it will not be deployed in the event of a vehicular crash. This is particularly true of the passenger airbag when a child or person of relatively small height is sitting in the passenger seat. Experience has shown that airbag deployment may cause severe or even fatal injuries to such persons. Airbag deployment should be suppressed in any case, not only when the passenger seat is occupied by a child or a short adult, but also when occupied by any object such as an item of baggage. There are methods for detecting the type of occupancy of the seat, and then when a certain type of occupancy is detected, the controller for the passenger airbag blocks its deployment in the event of a vehicular crash. Passenger airbag deployment must also be prevented if a child seat, in particular a child seat facing the rear, is positioned on the passenger seat. There are detection systems which deliver xe2x80x9cdo not deployxe2x80x9d information to a controller for the passenger airbag when a child seat is placed on the passenger seat. In the simplest case, the driver or passenger is able to deactivate the passenger airbag by simply operating a switch whenever one of the above-mentioned seat occupancy situations occurs.
With all these methods, only the transmission of ignition commands to the ignition device of the passenger airbag is suppressed. However, since the airbag together with its gas generator and its ignition device remain installed in the vehicle, there is the danger that it may nevertheless be deployed in error, e.g., because of an electrostatic discharge. False deployment may also occur due to an excessively high temperature, e.g., when there is a fire in the vehicle. A 100% safety against faulty deployment of the airbag may be achieved only by removing the entire airbag module together with the gas generator and the ignition device from the vehicle. Not just those skilled in the art but also the driver and/or the passenger should be capable of removing the airbag module from the vehicle and reinstalling it again without using any tools.
Therefore, the object of the present invention is to provide an airbag module of the type defined in the preamble which may be installed and removed with only a few manipulations. There should be no possibility of the airbag being deployed due to improper handling.
This object is achieved with the features of claim 1 by the fact that the airbag module is provided with a locking device and an electric contacting device which cause the airbag module to be mechanically locked when inserted into a receiving shaft provided in the vehicle and cause an electric connection to be established between the ignition device and a controller. The locking device and the electric contacting device are designed so that when the airbag module is inserted into the receiving shaft, it is first locked mechanically and then the electric contact is established, and on removal of the airbag module from the receiving shaft, the electric contact is released first and then the mechanical lock is released.
An airbag module having the features mentioned above may be removed from the receiving shaft and reinserted again with just a few manipulations without the use of special tools. Thus anyone, for example, the driver or the passenger, may uninstall the passenger airbag in particular to have 100% certainty that the passenger airbag will not be deployed when the occupancy situation of the passenger seat requires this. The sequence of mechanical locking and electric contacting claimed according to the present invention guarantees that deployment signals cannot in any case be transmitted to the airbag module if the airbag module is not securely locked in the receiving shaft. If the airbag module is first locked in the receiving shaft and subsequent electric contacting is possible only after correct locking, this rules out the possibility of an improperly locked airbag module being deployed. In a rear-end collision, for example, an incorrectly locked airbag module might be ripped out of the receiving shaft and might injure occupants of the vehicle.
Advantageous refinements of the present invention are derived from the subclaims.
Preferably at least one operating element is provided which is connected at one end to the locking device which establishes a frictional connection between the airbag module and a supporting frame in the receiving shaft and at the other end is connected to a contacting device which establishes a connection between contacts on the airbag module and the corresponding contacts in the receiving shaft. The operating element is advantageously a lever which is accessible from the front side of the airbag module facing out of the receiving shaft and is pivotable in two directions. When the lever is pivoted in one direction, first the locking occurs and then the electric contacting, and when the lever is pivoted in the other direction, first the electric contacts are released and then the lock is released.
It is expedient that the contacts of the ignition device are automatically short circuited on removal of the airbag module from the receiving shaft. With this short circuit, the controller detects that the airbag module has been removed together with its ignition device and the controller is then able to activate an airbag deactivation display in the vehicle.
The contacting device may be composed of connector pins and jacks, the connector pins or the jacks being arranged on the airbag module and the jacks or the connector pins being arranged in the receiving shaft. The contacting device is likewise composed of a transformer having a first pot-type core having one or more windings and a second pot-type core having one or more windings, one of the two pot-type cores being arranged on the airbag module and the other pot-type core being arranged in the receiving shaft.